The present invention generally relates to radars, and more particularly relates to weather radars, and even more particularly relates to methods and systems for using multiple sweeps to map terrain with modern pencil beam weather radars.
In recent years, avionics engineers have endeavored to improve safety of flight and reduce pilot workload. Often, it is difficult to simultaneously achieve these two desirable results. One example of this is in the area of weather radar where pilots have used weather radars to provide supplemental navigation information through terrain mapping.
Pilots have frequently used weather radars to map the terrain in front of an aircraft. They have used a manual antenna tilting technique where the tilt angle of the transmitted radar beam is adjusted in flight to provide multiple terrain strip views from the radar. The term xe2x80x9cbeamxe2x80x9d is used herein to refer to the entire transmission area during a single azimuthal sweep of the antenna at a single tilt angle. While these pilot-controlled tilt adjustments have been used extensively in the past, they do have some drawbacks.
First of all, current generation weather radars have pencil beam antennas, which paint only a strip of ground returns at any one time, when the radars are directed downwardly so as to involve the ground. (Note: Previous generations of radars included antennas whose beam shape could be xe2x80x9cspoiledxe2x80x9d or modified to produce a relatively uniform illumination of the ground.) For the pilot to use a radar with a pencil beam (narrow beam) to scan the terrain at relatively short ranges in front of the aircraft, the pilot must command several different tilt values during sequential antenna scans and mentally integrate the individual radar strip-like images together. Recently, weather radars have been introduced which utilize on-board position determination equipment, such as GPS, and terrain databases to automatically control the tilt angle of the radar. However, any automatic tilt control system which uses a single pencil beam, still will only sample a strip of ground return and require the pilot to intervene to mentally integrate multiple antenna sweeps at different (albeit automatic) antenna tilt angles to produce a complete radar ground map.
Consequently, there exists a need for improved methods and systems for using modern pencil beam weather radars for detecting and displaying ground map information in an efficient manner.
It is an object of the present invention to provide a system and method which enhances safety of flight.
It is a feature of the present invention to utilize a weather radar which uses multiple sweeps to generate a single ground map display image to the pilot.
It is an advantage of the present invention to achieve improved efficiency in interpreting the significance of returns displayed on a weather radar display.
It is another advantage of the present invention to produce a complete broad coverage ground map display to the pilot even when the radar uses a modern pencil beam antenna.
The present invention is an apparatus and method for detecting and displaying ground information, which is designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out in a xe2x80x9cone scan to one image-lessxe2x80x9d manner in a sense that the multiple scans or antenna sweeps are used to generate a single image of weather information.
Accordingly, the present invention is a system and method including a ground radar detection, processing and display apparatus which uses information from multiple scans to generate a single displayed ground information image.